This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In search of the mechanisms that govern pluripotency and embryonic stem cell (ESC) self-renewal, a growing list of evidence highlights chromatin as a leading factor, controlling ESC maintenance and differentiation. Nuclear envelope (or nuclear lamina) has been proved to play an important role in maintaining chromosomal organization and function. Therefore, we hypothesize that the unique nuclear envelope of ESC could participate in regulation of ESC maintenance and differentiation. Our aim is to identify and compare lamina (a constitutively expressed lamina protein) binding partners from human fibroblasts and ESC extracts by a series of pull-down assays, and subsequent analysis by multidimensional protein identification technology (MudPIT) followed by stringent data filtering. This study would reveal a novel role of nuclear lamina in stem cell biology.